Injector time…

[darkness]

After our short trip out of town, pretty sure I need injectors. Balance rates were pretty high when I bought it, and after running some Hot Shots Secret thru they have come down a lot. But now the main injection rate is down and sometimes has a lope and no balance rates at all. The truck seemed very lack luster climbing the grade out of town, and it was hard to keep the egt’s down. Could be my tuning cause I’m not very good at it yet but I don’t think so. I’m also concerned with the amount of blow-by. It’s not pressurized, but seems a little high. I did a compression test and things look ok. Here’s some pics and a video.

Source: https://youtube.com/shorts/X2ahM6-Ooec?si=-RkjvAXocxx9d9Ws
The cap fell off as it sits at an angle and vibrated off.

 

[Bdsankey]

Compression is a little low and you have a spread of ~11.11% from highest to lowest, ideally sub 10% is what you'd want. Also, the GM service limit is ~300psi so you're close but not quite there.

I've certainly seen (and owned) engines with worse blow by. It's not super concerning. Based on your symptoms it certainly may be time for injectors. Is it hazing at idle much?

 

[2004LB7]

Lowish compression could also just be the tester. Or even the length of hose. But it won't fix the spread.

 

[darkness]

It most definitely could’ve been the tester (me). I gave it 6 revolutions. Some might have been 7. Or not on the next compression stroke at 6. I was just counting a certain distinct puff. Do you crank until the gauge stops moving? I’m using the Harbor Freight Maddux kit.
As far as hazing, not really. Strong exhaust smell at idle though.

 

[2004LB7]

Normally, pull all the glow plugs and pull the EDU fuse to keep it from squirting fuel. Then with battery on a good charger, do compression check. I like to go until the gauge stops. It usually only takes a few revolutions to peak.

It's my understanding that the HF kits run on the low side.

 

[Bdsankey]

Normally, pull all the glow plugs and pull the EDU fuse to keep it from squirting fuel. Then with battery on a good charger, do compression check. I like to go until the gauge stops. It usually only takes a few revolutions to peak.

Same here, I go until it stops moving.

It's my understanding that the HF kits run on the low side.

Also agreed, the HF testers tend to be a bit low.

 

[darkness]

Could be some of the problem. On a hunch, I gave one cylinder a couple more revolutions after the initial read and got about 15 more psi. In all honesty I was just looking for an anomaly that would rear its ugly head.

 

[2004LB7]

Hopefully it's just injectors then. How many miles do you have on them?

 

[1FastBrick]

That Poor Kodiak...

 

[darkness]

Hopefully it's just injectors then. How many miles do you have on them?

If they are original, 135,000 miles. I don’t know how hard it was beat on, but it was a box truck used by the paint department at an equipment rental company.

 

[darkness]

That Poor Kodiak...

You’re telling me. Even before the trans build, it drove great around town. It’s just not happy with a load behind it.

 

[Bdsankey]

Is this a bad time to say Dynomite is on a 10% sale the entire month of Feb for duramax products?

 

[1FastBrick]

If they are original, 135,000 miles. I don’t know how hard it was beat on, but it was a box truck used by the paint department at an equipment rental company.

So probably rode hard and put away wet... that explains the blow by...
They probably never put any additives in it for the fuel system.

 

[1FastBrick]

Is this a bad time to say Dynomite is on a 10% sale the entire month of Feb for duramax products?

Tell Fleece to have a sale too...

 

[Bdsankey]

Tell Fleece to have a sale too...

I wish haha

 

[darkness]

Is this a bad time to say Dynomite is on a 10% sale the entire month of Feb for duramax products?

I checked your page the other day for sales . I’ll be getting ahold of you.

 

[darkness]

Tell Fleece to have a sale too...

Yeah, with the money I’ll be saving on injectors, I could get a tap shift.

 

[TheBac]

Curious, have you tested the CP3 output?

I see nothing wrong with those compression numbers.

 

[darkness]

I haven’t done any testing but it holds rail no problem.

 

[1FastBrick]

Just curious, Don't the Kodiak's use a different block from a regular 2500 that has a special provision for the chassis mount in the front of the block or something?

I recall seeing something in the various builds from Gasout I believe his username was?

I know other things like the pans are different.